Underground and aboveground bulk storage tanks are very widely used for containment of all manner of fuels and chemicals. Tanks of this nature are typically fabricated from steel or glass fibre reinforced plastic, and depending upon the environment of the installation and the material being contained, can be subject to leakage. It is significant to note that by some estimates, nearly one-third of the underground storage tanks in the United States may be subject to some leakage.
Depending upon the nature of the material being stored, unchecked leakage of a tank can be very detrimental to the environment. Leakage of hazardous or corrosive materials can percolate into ground-water below the storage facility, with resultant contamination. At the very least, the cost of material which is lost or contaminated can be quite high.
In view of this, well-designed storage facilities are provided with so-called secondary containment devices in association with underground and aboveground storage tanks, piping systems, processing pits and ponds, and the like. In fact, such secondary containments are required by law in many locations. To this end, expansive, sheet-like liners of suitably impervious material are employed such as for disposition in the excavation for an underground storage tank, or for positioning within a suitable depression or pit beneath an aboveground tank or piping system.
While certain thermoplastic polyester elastomers can be formulated to be highly impervious to diesel fuel, gasoline, chemical solvents, and other volatile and/or corrosive materials, sheets of such thermoplastics typically do not exhibit sufficient strength and resistance to puncture as is desirable for use as secondary containments. Needless to say, the very nature of the application of secondary containments requires extremely high resistance to puncture and leakage. Additionally, the widely differing requirements of various applications, as well as the typically large physical dimensions required, mandate that a secondary containment arrangement lend itself to consistent and reliable manufacture, versatile use, and efficient installation.
There also exists a need for containment structures suited for handling and storage of hazardous or contaminated materials. While the above-described secondary containments are intended to prevent environmental contamination, it is nevertheless sometimes necessary to store or transport soil or other material which has been contaminated. Again, a structure exhibiting a high degree of imperviousness to corrosive or hazardous substances is required, with puncture-resistance being necessary to facilitating handling. Further, such an arrangement is preferably configured for closing and sealing after the material to be contained has been placed therein.
With the above goals in mind, the containment structure liner of the present invention has been particularly configured for very high resistance to puncture and leakage, while at the same time lending itself to cost-effective manufacture, highly versatile use, and straightforward installation.